“…However, for patients with long‐term use and elevated concentrations of L‐dopa, there is an association with various side effects, such as loss of appetite, gastritis, insomnia, nausea and vomiting, dyskinesia, paranoia or even hallucinations 2,4,5 . A number of analytical methods are used for the determination of L‐dopa, such as high performance liquid chromatography, 6–9 electrochemiluminescence, 10 spectrophotometry, 11 flow injection analysis, 12 capillary zone electrophoresis, 13 and fluorescence methods 14,15 . Although these methods provide high sensitivity, a series of disadvantages could be identified, such as complexity, long testing time and high costs 16–19 .…”